1. Field of the Invention
This invention relates to body-support floatation systems and more particularly to a floatation system including an reversible gel encased in a flexible bladder for such body-support.
2. Description of the Prior Art
It has been known for some time that the human body needs adequate rest to maintain both physical and mental wellbeing. Medical studies show that the average person needs approximately eight hours of rest per twenty-four hour period. Of course, the type of body-support structure used during the rest period has a direct relationship to the adequacy of the rest period.
An an out-growth of the studies to determine the cause of pressure necrosis including decubitus ulcers (commonly called bed sores), it has been concluded that equalized pressure distribution on the body over the entire body-support structure is of primary importance in relieving stress during the rest period. In order to accomplish uniform pressure distribution in body-support structures, inner-spring cushion structures, such as those of the foam rubber and pneumatic type have commonly been employed. However, such structures still can cause areas of localized pressure which restrict blood flow to disrupt the rest period (and if continued for a long period of time, cause bed sores).
Recent efforts to find body-support structures with ideal uniform pressure distribution have resulted in development of liquid support structures generally classified as floatation systems. The most common floatation system, is formed of a flexible bladder filled with a non-compressible liquid, usually water. Such a system equally distributes pressure over all areas of the body in contact with the support structure. However, to provide sufficient support for the average human body, requires a structure of about 1500 pounds in weight. In a structure of this size, motion of the water within the bladder can be objectionable. Another drawback to the use of floatation systems is that the water within the bladder, being stagnate, promotes growth of bacteria which may necessitate the laborious task of periodically emptying the bladder and refilling it with fresh water.
In order to reduce both the weight and motion of the water-containing floatation system, organic fluid-like gells of increased viscosity (with respect to water) have been used, as taught by U.S. Pat. Nos. 3,308,491; 3,548,420; and 3,737,930. The use of gells of increased viscosity will reduce motion within the bladder and will enable an equivalent amount of support to be produced with a reduced quantity of liquid. Organic substances are, however, relatively costly. Further, they are subject to deterioration after a period of time, and replacing the gel presents significant problems not found in standard water-containing floatation system.